Textile treatment compositions suitable for providing fabric softening and static control benefits during laundering are well known in the art and have found widespread commercial application. Conventionally, rinse-added fabric softening compositions contain, as the active component, substantially water-insoluble cationic materials having two long alkyl chains. Typical of such materials are di-hardened tallow dimethylammonium chloride and imidazolinium compounds substituted with two hardened tallow groups. These materials are normally prepared in the form of a dispersion in water and it is generally not possible to prepare such aqueous dispersions with more than about 6% of cationic softener without encountering severe product viscosity and storage-stability problems. Although more concentrated dispersions of softener material can be prepared as described in European Patent Application No. 406 and Bri. Pat. No. 1,601,360 by incorporating certain nonionic adjunct softening materials therein, such compositions tend to be relatively inefficient in terms of softening benefit/unit weight of active; moreover, product viscosity and stability problems become increasingly unmanageable in more concentrated aqueous dispersions and effectively limit the commercial range of applicability to softener active levels in the range from about 15% to about 20%.
Cationic softener materials are normally supplied by the manufacturer in the form of a slurry containing about 70%-80% of active material in an organic liquid such as isopropanol sometimes containing a minor amount of water (up to about 10%). Retail fabric softening compositions are then prepared by dispersion of the softener slurry in warm water under carefully controlled conditions. The physical form and dispersibility constraints of these industrial concentrates, however, are such as to preclude their direct use by the domestic consumer; indeed, they can pose severe processing problems even for the industrial supplier of retail fabric softening compositions.
In United Kingdom Application No. 2,007,734A, fabric softener concentrates are disclosed containing a mixture of a fatty quaternary ammonium salt having at least one C.sub.8 -C.sub.30 alkyl substituent and an oil or substantially water-insoluble compound having oily/fatty properties. The concentrates are said to be easily dispersed/emulsified in cold water to form fabric softening compositions of adequate viscosity, thereby facilitating softener production by a manufacturer without the need for special mixing equipment. Applicants have found, however, that although these concentrates go some way towards alleviating the problems of the industrial manufacturer, the compositions are still highly deficient from the viewpoint of providing acceptable cold-water dispersibility, formulation stability at both elevated and sub-normal temperatures, together with satisfactory softening performance. As a result, the prior art compositions are essentially of limited value as retail compositions for direct use by the domestic consumer.
The present invention therefore provides a concentrated liquid textile treatment composition having improved stability at both elevated and sub-normal temperatures under prolonged storage conditions and good cold-water dispersibility in the dispenser of a domestic automatic washing machine together with excellent softening, anti-static and fabric rewettability characteristics across a broad range of fabric types.